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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 82 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.Take 43 and take away the sum of its digits. What do you get?
  2. 2.3?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 35 and take away the sum of its digits. What do you get?
  4. 4.Take 15 and take away the sum of its digits. What do you get?
  5. 5.188? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 57 and take away the sum of its digits. What do you get?
  7. 7.Take 26 and take away the sum of its digits. What do you get?
  8. 8.38?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 92 and take away the sum of its digits. What do you get?
  11. 11.Take 99 and take away the sum of its digits. What do you get?
  12. 12.Take 23 and take away the sum of its digits. What do you get?
  13. 13.Take 91 and take away the sum of its digits. What do you get?
  14. 14.23?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.664? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 52 and take away the sum of its digits. What do you get?
  17. 17.653? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.62?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.7?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 93 and take away the sum of its digits. What do you get?
  21. 21.Take 54 and take away the sum of its digits. What do you get?
  22. 22.?060 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 46 and take away the sum of its digits. What do you get?
  24. 24.1?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.25?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?428 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.65?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.5?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 65 and take away the sum of its digits. What do you get?
  32. 32.?489 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 83 and take away the sum of its digits. What do you get?
  34. 34.17?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.283? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 19 and take away the sum of its digits. What do you get?
  37. 37.3?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?697 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 50 and take away the sum of its digits. What do you get?
  40. 40.Take 70 and take away the sum of its digits. What do you get?

Answer key

  1. 36
  2. 5
  3. 27
  4. 9
  5. 1
  6. 45
  7. 18
  8. 6
  9. 6
  10. 81
  11. 81
  12. 18
  13. 81
  14. 5
  15. 2
  16. 45
  17. 4
  18. 6
  19. 1
  20. 81
  21. 45
  22. 3
  23. 36
  24. 3
  25. 1
  26. 7
  27. 4
  28. 8
  29. 1
  30. 4
  31. 54
  32. 6
  33. 72
  34. 9
  35. 5
  36. 9
  37. 9
  38. 5
  39. 45
  40. 63

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